1. Field of the Invention
This invention relates to systems for chilling pouches of food and particularly to a chilling system having a conveying apparatus that automatically conveys pouches of food through a chilling step. In the context of this specification, a conveying apparatus will be understood to mean an apparatus such as a continuous belt or length of parallel rotating rollers that transports a plurality of items from an upstream (entrance) end to a downstream (exit) end in a continuous line (one after the other).
2. Prior Art and Information Disclosure Statement
In many instances, the food industry has adopted the use of plastic pouches or bags as a replacement for rigid containers such as barrels or metal drums formerly used to pack and ship a wide variety of foods. Foods that are presently packed and shipped in pouches include tomato products, various toppings such as chocolate and strawberry, soups, ets. The primary reason for the popularity of pouches for this purpose is cost, not only in terms of the cost of the container, but also in terms of the versatility provided in building equipment to handle these containers.
Typically, the temperature of the pouches of food discharged from a filler is 190.degree.-200.degree. F. The temperature of the pouches must be reduced to 105.degree.-110.degree. F. in order that the pouch can be handled and stored to ambient temperature without deterioration of the product. This reduction in temperature should take place in about 20 to 45 minutes.
The pouches are generally discharged from the filler one pouch at a time. If the pouches must pass through the chiller in a single line, then the length of the line would be excessively long. Therefore, the industry has adapted conveying apparatus that forms rows of pouches that progress through the chiller.
FIG. 1 is a top view showing the indexer 10 of a conveying apparatus of the prior are having a single line of product 12 on a continous belt 14 coming from the filler and moving in the direction from left to right as shown by the arrow. The index station comprises a line of retractable gates 18, each gate 18 coupled to a pneumatic cylinder (not shown), such that, as each pouch 12 carried by the belt 14 reaches its position in the indexer, the respective gate 18 comes down to prevent further movement of the pouch. When all the gates 18 are down, as detected by an electric eye, a set of pushers 20 move the pouches 12 onto a transfer belt in rows 16, with five pouches to a row, that carry the rows of pouches through the chiller.
The rows of pouches pass through the chiller three times by moving on a top level, an intermediate level, and a lower level in succession. This three pass construction requires a shorter chilling machine and also conserves the amount of cooling water needed. The pouches are transferred from one level to the next lower level by an array of rollers which guide the pouches but more or less allow the pouches to "free fall" from one level to the next lower level.
Damage to the pouches during their trip through the chiller system of the prior art occurred because of a number of reasons discussed below. The problem has been exacerbated by the introduction of thinner flexible plastic pouches.
One source of damage to the pouch was that the belt continued to run after the pouch had been stopped by the gate in the indexer thereby subjecting the pouch to rubbing from the belt as well as pushing a portion of the pouch under the nearest gate.
Another source of damage to the pouches is the rough treatment from the guide rollers as the pouch free falls to the next lower level in the chiller.
Another problem is that the retracting gate is sometimes jammed by an incoming pouch. Pouches of plastic can be jammed under the gate of the prior art indexer because the plastic is comparatively thin and flexible.
Another problem is that the conveying system is designed to receive only a fixed number of pouches in a row determined by the number of gates across the conveyor belt. This characteristic places a limit on the rate of throughput of pouches regardless of the size of the pouches.